1992 Dodge Caravan Van wobbles when slowing down to stop

Shakes or Wobbles problem
1992 Dodge Caravan 6 cyl All Wheel Drive Automatic

Hello, I just bought a 92 Dodge Grand Caravan and it wobbles or kinda jerks when slowing for a stop. The seller told me they just had the brakes & rotors done, can that cause the wobble if they weren't adjusted properly?
Also my oil gauge is staying a little below the first line above the L even after adding 2 quarts of oil, where should the gauge range between the H & L ?